University of Oulu

Oyama, S.‐i., Kubota, K., Morinaga, T., Tsuda, T. T., Kurihara, J., Larsen, M. F., … Cai, L. (2017). Simultaneous FPI and TMA measurements of the lower thermospheric wind in the vicinity of the poleward expanding aurora after substorm onset. Journal of Geophysical Research: Space Physics, 122, 10,864–10,875. https://doi.org/10.1002/2017JA024613

Simultaneous FPI and TMA measurements of the lower thermospheric wind in the vicinity of the poleward expanding aurora after substorm onset

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Author: Oyama, Shin-ichiro1,2; Kubota, Ken1,3; Morinaga, Takatoshi4,5;
Organizations: 1Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan
2Space and Upper Atmospheric Sciences Group, National Institute of Polar Research, Tachikawa, Tokyo, Japan
3Now at KUBOTA, Inc., Osaka, Japan
4Electronic and Photonic Systems Engineering Course, Kochi University of Technology, Kami, Japan
5Now at Nishimu Electronics Industries Co., Ltd, Fukuoka, Japan
6Department of Computer and Network Engineering, University of Electro-Communications, Chofu, Japan
7Department of Cosmosciences, Hokkaido University, Sapporo, Japan
8Department of Physics and Astronomy, Clemson University, Clemson, SC, USA
9Ionospheric Physics Unit, University of Oulu, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.9 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe201902215930
Language: English
Published: American Geophysical Union, 2017
Publish Date: 2019-02-21
Description:

Abstract

Lower thermospheric wind fluctuations in the vicinity of an auroral arc immediately before and after a substorm onset were examined by analyzing data from a ground‐based green line Fabry‐Perot interferometer (FPI; optical wavelength of 557.7 nm) at Tromsø, Norway, and in situ measurements from a trimethyl aluminum (TMA) trail released from a sounding rocket launched during the Dynamics and Energetics of the Lower Thermosphere in Aurora 2 (DELTA‐2) campaign on 26 January 2009. Soon after the rocket launch but before disappearance of the TMA trail, a substorm onset occurred. The DELTA‐2 TMA experiment appears to be the first case in which the substorm onset occurred during the TMA wind measurement. It is known that energy dissipation induced by the ionospheric closure current is compacted at the poleward side of the discrete arc in the ionospheric morning cell. Both FPI and TMA measurements were made at the poleward side, but the FPI measured winds nearer to the poleward edge of the arc than the TMA by 110–130 km. The FPI winds at distance of 53–74 km relative to the arc edge showed clear fluctuations immediately after the substorm onset, but there was no obvious similar fluctuation in the TMA‐measured winds. The difference in the response at the two locations suggests that energy dissipation sufficient to be detected as the FPI/TMA wind perturbations was confined to the area from the poleward edge of the arc to a relative distance shorter than 163–203 km but longer than 53–74 km in this event.

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Series: Journal of geophysical research. Space physics
ISSN: 2169-9380
ISSN-E: 2169-9402
ISSN-L: 2169-9380
Volume: 122
Issue: 10
Pages: 10,864 - 10,875
DOI: 10.1002/2017JA024613
OADOI: https://oadoi.org/10.1002/2017JA024613
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
Subjects:
Funding: This research has been supported by a Grant‐in‐Aid for Scientific Research (15H05747, 16H06286, 16K05569, and 16H02230) and Special Funds for Education and Research (Energy Transport Processes in Geospace) from MEXT, Japan.
Copyright information: © 2017. American Geophysical Union. All Rights Reserved.